Information storage devices are in wide spread use, and are used to store and retrieve large amounts of data. Such information storage devices generally include a rigid media for storing information, a read/write device for creating and accessing the information, and an actuator assembly for positioning the read/write device over the rigid media. One common example of such an information storage device is a hard disk drive having one or more rotating magnetic disks over each of which a head suspension and a head slider are positioned. Each of the head suspensions is attached to an actuator assembly, which positions the suspensions and sliders over the rotating disks.
An actuator assembly used in a disk drive typically includes an actuator block mounted to the frame of the information storage device, a motor for rotating the actuator block, and one or more arms, attached to the actuator block, to which a read/write device is mounted. Various methods for attaching the arms to the actuator block have been developed. One such method is known as swaging or ball staking. In this method, a boss attached at an end of an actuator arm is inserted in a hole in the actuator block. The actuator arm is then deformed and engaged with the actuator block by forcing a round ball through the boss.
Another method for attaching arms to an actuator block is demonstrated in the Hoffmann et al. patent, U.S. Pat. No. 5,497,282. The Hoffmann et al. patent shows an actuator hub having radially extending actuator arms. Each of the radially extending arms has slots formed in an edge of the arm, and a pair of bosses on the end of a mounting plate are inserted into the slots of the arm. The bosses are then swaged to connect the mounting plate to the radially extending arm.
Another method for attaching arms in an actuator assembly is shown in the Baasch et al. patent, U.S. Pat. No. 5,495,375. The Baasch et al. patent shows a plurality of arms having a C-shaped opening at an end that removably engages an actuator member. Each arm is individually self-locked into the actuator block at the C-shaped opening of the arm.
Conventional methods for attaching arms to an actuator block such as those described above, however, have certain disadvantages. Specifically, the large vertical force that must be applied to the actuator assembly to swage an arm boss into an actuator hole can warp or otherwise permanently deform the actuator block and/or the arm. In addition, arms swaged to an actuator block cannot be selectively reworked or replaced because the swaging process cannot be reversed. The use of a boss on the arms also increases the size of the actuator assembly because the spacing between the arms must be increased to accommodate the boss. Moreover, arms having a self-locking C-shaped opening such as those shown in the Baasch et al. patent may not provide sufficient torque retention to securely hold the arm in place as the actuator block quickly rotates to position the read/write device over the rigid media.
There is therefore a continuing need for an improved actuator assembly. Such an improved assembly should securely hold the elongated arms in place as the actuator block rotates. In addition, it is desirable to be able to selectively rework and replace the arms rather than replacing the entire actuator assembly. An attachment system that does not require large vertical forces to attach the arms to the actuator block and that provides an overall lower profile actuator assembly is also highly desirable.